螺螨酯对山楂叶螨的生物活性和防治效果

螺螨酯是一种高效、低毒、广谱性杀螨剂,为研究螺螨酯对山楂叶螨Tetranychus vinnensis各螨态的影响,用24%的螺螨酯悬浮剂分别处理山楂叶螨卵、若螨和成螨。试验结果表明,螺螨酯对螨卵和若螨活性高,其致死中浓度LC50分别为0.76mg/L和19.07mg/L。采用玻片浸渍法分别用螺螨酯48、96、192mg/L处理成螨,48h校正死亡率为2.6%、19.4%、19.4%。采用喷洒叶片法,分别用螺螨酯1.5、3、6、12、24和48mg/L处理成螨,成螨的繁殖力显著下降。在温室盆栽苹果上,药后21d螺螨酯60mg/L处理山楂叶螨的减退率为100%,显著高于对照药剂四螨嗪250mg/L的减退率33.3%。总之,螺螨酯对山楂叶螨各阶段都有良好的控制效果,可以作为防治该螨的推荐药剂,施药适宜时期为第1代卵期。

Effects of spirodiclofen on activity and efficacy of Tetranychus viennensis

Spirodiclofen（SC） is an efficient,low toxicity and broad-spectrum acaricide.In order to study the effectiveness of spirodiclofen in controlling Tetranychus vinnensis,eggs,immature and adults of this mite were treated with a range of concentrations of 24% SC.The results show that spirodiclofen was most efficient at killing eggs and nymphs;the LC50 of these life stages was 0.76 mg /L and 19.07 mg /L respectively.The corrected mortality rates of adult mites treated by slide-dipping with 48,96 and 192 mg /L of spirodiclofen were 2.6%,19.4% and 19.4% after 48 h exposure.Female fecundity and fertility was significantly reduced when they were sprayed directly with concentrations of 1.5,3,6,12,24 and 48 mg /L.In a glasshouse trial,mite numbers were reduced by 100% 21 days after treatment with 60 mg /L of spirodiclofen.This was much more effective than the 33.3% reduction observed following treatment with 250 mg /L of clofentezine.In conclusion,spirodiclofen was most toxic to eggs and nymphs of T.vinnensis.Although adult females were less susceptible,their fecundity and fertility were significantly reduced.We therefore recommend the application of this pesticide for controlling mites in orchards.It is particularly suitable for spraying during the egg-stage of the first generation.